The University of Chicago Medical Center is seeking patients diagnosed with atrial fibrillation (irregular heartbeat) who are taking the blood thinner warfarin (i.e. Coumadin®) to participate in a research study.

The study could ultimately lead to patients with atrial fibrillation never having to take blood thinners again for this condition.

Atrial fibrillation is a heart condition where the upper chambers of the heart beat too fast, says John Lopez, MD, one of the two study directors. The condition can cause blood to stagnate and form clots in the heart's left atrial appendage. If they escape, these clots can cause strokes, he explains.

The American Heart Association says 2.2 million Americans have atrial fibrillation and that about 15 percent of all strokes occur in people with atrial fibrillation.

The Medical Center is one of four in Illinois, along with 56 other hospitals around the world in a large randomized trial studying the effectiveness of a device implanted in the heart designed to keep blood clots that have formed in the heart's left atrial appendage from ever entering the bloodstream.

First, a tube is inserted through a vein in the upper leg, all the way to the heart. Once the tube is in the correct position, pictures are taken to measure the heart's left atrial appendage. These measurements determine the size of device to be used. The device, called the WATCHMAN®, is guided through the tube and positioned in place. Pictures are then taken again to verify correct placement. Once verification is made, the WATCHMAN® is released to permanently remain in the heart.

People taking blood thinners to keep clots from forming typically require frequent monitoring and sometimes have diet and other drug interactions causing them to stop taking these drugs.

Those enrolled in the study will be randomized to either receive the WATCHMAN® or continue on long- term medical therapy with warfarin, which if the participant needs assistance, will be provided free of charge. Participants will make approximately four to six visits to the medical center during the first year and then twice a year thereafter for follow-up.

"As is the case in all randomized studies like this, patients may not necessarily benefit directly from the research," explains Bradley Knight, MD, the study's other director. "However, information obtained during the course of this study may contribute to a better understanding of atrial fibrillation. And patients who receive the WATCHMAN® may be able to stop taking blood thinners and may no longer need to have blood drawn for dose adjustments," he adds.

Patients interested in participating in the study at The University of Chicago Medical Center may call (773) 834-8399 for more information.